Allegations of inappropriate and controlling behaviour had been made against the 50-year-old.
“Red Bull is confident that the investigation has been fair, rigorous and impartial,” a spokesperson for the company said.
Horner, who has led Red Bull since 2005, denied the allegations.
He will remain in his role as team principal and chief executive of Red Bull F1.
The statement, which was issued by Red Bull’s head office in Austria, added that the “grievance has been dismissed” and that “the complainant has a right of appeal.”
Red Bull provided no details of the allegations or the investigation.
The statement said: “The investigation report is confidential and contains the private information of the parties and third parties who assisted in the investigation, and therefore we will not be commenting further out of respect for all concerned.
“Red Bull will continue striving to meet the highest workplace standards.”
Details of the allegations emerged on 5 February.
The decision by Red Bull, which follows a meeting of the company’s board of directors, comes after an eight-week investigation, which became public early this month.
Earlier on Wednesday, at the season-opening Bahrain Grand Prix, Lewis Hamilton said the investigation was a “really important moment to make sure we stand true to our values”.
The seven-time world champion added: “We always have to do more to try to make the sport and the environment people work in feel safe and inclusive, and any allegations have to be taken very seriously.
“It will be really interesting to see how it is dealt with and the effect it may well have on the sport.”
Last week, US car giant Ford, which will be Red Bull’s engine partner in F1 from 2026, made clear their annoyance with the time the investigation was taking and Red Bull’s lack of clarity.
Ford CEO Jim Farley wrote a letter to the team that was leaked to the Associated Press, external, in which he said he was “increasingly frustrated, however, by the lack of resolution or clear indication from you about when you anticipate a fair and just resolution of this matter.
“We are likewise frustrated by the lack of full transparency surrounding this matter with us, your corporate partners, and look forward to receiving a complete account of all findings.”
Red Bull’s three-time world champion Max Verstappen said in Bahrain he was “trusting the process of the investigation”.
He was asked twice whether he had full faith in Horner as team principal and each time ducked the question.
How we got here
When the allegations first emerged on 5 February, Red Bull issued a statement saying it was taking the matter “extremely seriously” and starting an “independent investigation”.
On the same day, Horner told Dutch newspaper De Telegraaf, external “I completely deny these claims”.
He was then interviewed by a lawyer for several hours on 9 February but the hearing finished without resolution.
The allegations overshadowed the launch of Red Bull’s new Formula 1 car on 15 February, when Horner again denied the allegations and told the BBC it was “a distraction” for his team.
He said he had the full backing of all Red Bull’s owners. The company is owned 51% by Thailand’s Yoovidhya family and 49% by the family of the late Dietrich Mateschitz in Austria.
During pre-season testing, Mercedes team principal Toto Wolff called for the investigation to be transparent and said it was “an issue for all of Formula 1”.
F1, the sport’s commercial rights holders, had urged Red Bull to clarify the matter “at the earliest opportunity after a fair and thorough process”.
Governing body the FIA has said it will not comment until the investigation is complete, but added: “The FIA remains committed to upholding the highest standards of integrity, fairness and inclusivity within the sport.”
Who is Horner?
Horner has been Red Bull team principal since they first started on the F1 grid in 2005 and has gone on to win seven drivers’ championships and six constructors’ championships with the team.
Having received an OBE in 2013, Briton Horner was appointed a CBE in the New Year’s Honours list last year after overseeing Red Bull’s record-breaking 2023 season in which the team won 21 of 22 races as Max Verstappen claimed his third world title.
Horner raced competitively as a youngster but retired aged 25 and set his sights on managing an F1 team.
He married Spice Girl Geri Halliwell in Bedfordshire in 2015.
